Apparatus for forming sheet metal elbows



Jan. 11, 1938.v c. J. HOLUB APPARATUS FOR FORMING SHEET METAL ELBOWSFiled 0G13. 17, 1936 6 SheeLS-Sheel. l

Jan. 11; 1938.

J. HOLUB APIARATUS FOR FORMIG SHEET METAL ELBOWS Filed Oct. 1'7, 1936 6Sheets-Sheet 2 Jan. 11,1938. Cl 1 HOLUB APPARATUS FOR FORMING SHEETMETAL ELBOWS Filed Oct. 17, 1 936 6 Sheets-Sheet 5 INVENTOR Jan. l1,1938.

c. J. HOLUB APPARATUS vFOR FORMING SHEET METAL ELBOWS 6 Sheets-Sheet 4Filed Oct. 17, 1936 INVENTOR 6 Sheets-Sheet 5 Jan. 1l, 1938. c. J. HoLUBAPPARATUS FOR FORMINGV SHEET METALy ELBOWS Filed oct. 17, 1936 N In Jan.11, 1938. c. J. HoLUB Y lAPPARATUS FOR FORMING SHEET METL EILBOWS Fle'dOct. 1'7, 1936 l 6 Sheets-Sheet 6 INVENTOR Patented Jan. 11, 1938 UNITEDSTATES PA'ENT @FFQE APPARATUS FOR FORD/.UNG SHEET METAL ELBO ApplicationOctober 17, 1936, Serial N0. 106,206

3 Claims.

This invention relates to a method and apparatus for making sheet metalelbows and, in particular, stove pipe elbows.

Devices of this general character have been known before, and examplesthereof are described and claimed in my prior Patents Nos. 1,517,678 and1,553,817. The object of this invention is to improve upon theconstructions disclosed in Ysaid patents, particularly in respect ofcertain automatic operations such as the clamping of the blank orworkpiece in position to be operated upon, and the means applying abrake to arrest operation of the device at intervals.

The improvements in details of construction comprising the presentinvention are illustrated in the accompanying drawings, and will becompletely described hereinafter.

In the drawings,

Fig. 1 is a side elevation;

Fig. 2 is an end view looking from the left in Fig. 1;

Fig. 2A is an elevation of a detail;

Fig. 3 is a view partly in elevation and partly in section along theline III-III of Fig. 1;

Fig. 4 is a central longitudinal section taken through the axis of amandrel on which the workpiece is disposed for corrugating and bendingoperations;

Fig. 5 is a sectional View through the mandrel taken along the line V--Vof Fig. 4;

Fig. G'is a side elevation of the parts shown in Fig. 5, looking fromthe' left in the latter;

Fig. 7 is a partial plan view of a clamping carriage movable on themandrel which is also shown in Figs. 5 and 6;

Fig. 8 is a view partly in elevation and partly in section along theline VIII-VIII of Fig. 5;

Fig. 9 is a partial sectional view along the line VIII-VIII of Fig. 5but looking in the direction opposite that of the arrows;

Fig. 10 is a partial section along the line X-X of Fig. 5;

Fig. 1l is a View partly in elevation and partly in section along theline XI-XI of Fig. 3;

Fig. 12 is a view partly in plan and partly in section along the lineXII-XII of Fig. 3;

Fig. 13 is a partial sectional View along the line XII-XEII of Fig. l2;

Fig. 14 is an end elevation of a bending ring or head adapted to beplaced over the end of the blank to receive the bending force appliedthereto; and

Fig. 15 is a plan View of a detail.

Referring now in detail to the drawings, the

(Cl. 15S-69.5)

apparatus comprises essentially a supporting bed or frame I and amandrel 2 carried thereby on a frame plate 3, the mandrel projectingtoward and through an opposed frame plate 4. A carriage 5 slidable onthe mandrel 2 and a bending ring 6 cooperate to support a tubular blank'I therebetween. The carriage 5 is fed forward along the mandrel 2 in astep by step fashion by a ratchet bar 8. segmental corrugating dies 9having overlapping ends intermittently form circumferential grooves orcorrugations in the blank, and the forward end of the latter is bentupwardly by engagement of bending arms IIJ with the bending ring S. Allthe parts are operated by a common drive II including a clutch I2 andbrake I3. Each of these parts will be described in detail underappropriate sub-titles.

The bed and frame The bed I may conveniently be composed of a suitablecasting mounted on supporting legs I4. 'Ihe frame plate 3 is mountedvertically thereon approximately midway between the ends thereof. Theplate l is similarly mounted adjacent one end of the bed. Spacer rods3a. extend between the plates 3 and 4 adjacent their upper ends. Adriveshaft I5 is journaled in a bearing I6 mounted at the end of the bedopposite that on which the plate 4 is mounted, and a bearing I'I formedon the plate 3. A pulley I8 is mounted on the shaft I5 whereby thelatter may be driven from any convenient power source. A pinion I9secured to the shaft I5 meshes with a gear 2U which runs free on a shaft2| journaled centrally and longitudinally of the bed I in bearings 22. Acountershaft 23 is journaled along one side of the bed I in bearings 2t.The shaft 23 is adapted to be driven by the shaft 2I through a gear andpinion drive, the gear thereof being shown at 25.

The mandrel As best shown in Fig. 4, the mandrel 2 has reduced ends, oneof which is firmly seated in a ring 26 pivoted to the plate 3 at 2l. Aset screw 2 8 permits the ring 2l to be so tilted as to position theother end of the mandrel accurately. The other end of the mandrelextends through an opening 29 in the plate li, the reduced end thereofbeing rmly secured to an anvil ring 30, the function of which willappear later. The carriage 5 includes a member 3i in the form of anannular ring or block slidable on the mandrel 2, being guided therealongby a ratchet bar 8 reciprocable in a suitable slot extendinglongitudinally of the Y mandrel, the bar 8 serving as a feather key forthe block or carriage 3l. A constant retracting force is exerted on thecarriage 3l by a counterweight 33 connected thereto by a cable 34trained around a pulley 35. The pulley is mounted on a bracket 3Ssecured to the plate 3|.

Semi-circular clamping jaws 31 are pivoteld to the carriage 3l on a pin38. These jaws have shoulders 39 which enter an annular groove formed inthe carriage, and are normally urged apart by a compression spring 4D,the ends of which are seated in sockets 4! formed in the abutting endsof the jaws. The jaws 31 have depending lugs 42 through which a camshaft 43 extends. A cam 44 adjustable on the shaft 43 is adapted tocooperate with a xed cam 45 on the depending lug of one of the jawswhereby to cause the jaws to contract on rotation of the shaft. A lever46 secured to the shaft 43 causes the latter to turn to contract orrelease the jaws.

A slide 41 is movable in guides 48 mounted on the side of the carriage3l. The slide has a pin and slot connection 49 with the lever 46. TheIlever 45 is automatically operated on advance and retraction of thecarriage 3l in a manner to be explained Yin greater, detail later.

As best shown in Fig. 4, an end of the tubular blank 1, which may beformed up into a cylinder from flat stock by any convenient means (notshown), is inserted in the annular space between the clamping jaws 3'5and the reduced end of the carriage 3l indicated at 59. The bending ring5 is slipped over the other end of the blank.

Worlcfeeding mechanism The ratchet bar 8 cooperates with a pawl 5! toadvance the carriage 3i step by step from the solid line position, inwhich it is shown in Fig. 4, to the position shown in dot and dashlines. The bar 8 is reciprocated periodically by means to be describedlater through a distance equal to the pitch of the ratchet teeththereon. The cooperation of the pawl 5I with the ratchet teeth causesthe carriage 3lY to move forward with thebar The outer end of the blank1 slides over the anvil ring 3G as the carriage 3l is advanced. Thefriction between the ring 3i! and the blank and between the carriage 3landthe mandrel prevents the latter from moving back with the bar t. Onbackward movement of the latter, the pawl slides in a vertical slot inthe carriage 3i and then engages the next tooth` The counterweight 33exerts a restraining force on the carriagel to prevent it from beingadvanced more than one step at a time, and to ensure close engagementbetween the pawl and the ratchet teeth, to posi-v tion the workaccurately for the corrugating operation.

VAlink 53 is pivotally mounted in Va bearing bracket 54carried on top ofthe carriage 3|. A lever 55 is pivoted to the link 53, and a detent 55is pivoted to the lever 55. The detent 56 has a hook 51 normallyengaging one end of the link 53. The detent 55 alsohas an inclinedsurface 58 adapted to cooperate with an abutment 5S on the plate 4having a similar surface. A spring latch 60 is carried on the lever 55.At its lower end, this latch has a projection capable of engaging undera cooperating projection on the pawl 5l to hold the latter in elevatedposition. With the parts in the position illustrated in Fig. e, however,a stud 5I is engaged by the latch Si) to cause the latter to release thepawl 5 l. When the carriage 3| has been movedforward tothe positionshown in dot and dash lines, engagement of the surface 58 of the detent56 with the abutment 59 tilts the lever 55 and places the latch 54 inposition to hold the pawl 5l in elevated position. Y

Ynism for the step by step feed of the carriage 3 I.

A stud 62 is adapted to engage the slide 41 to contract the clampingjaws 31 when the carriage 3l is in the position shown in solid lines inFig. 4. A stud 63 engages the slide 41 as the carriage 3l approaches theplate 4, to cause the clamping jaws to be released.

The mechanism for reciprocating the bar 8 includes a lever 32a connectedto the end of the bar 8 by a link 32h. The lever 32a is pivoted at 32eon the plate 3. A cam follower 32d is also pivcted to the plate 3 at320, and has a roller 32e at its lower end which traverses a groove in abarrel cam 32j carried on the shaft 2l. V.The link 32a has a projection32g extending into a slot intermediate the ends of the follower 32d. Setscrews 32h permit adjustment of the lever 32a relative to the follower32d, whereby the desired movement of the ratchet bar 8 may be obtained.

The corrugatz'ng dies and dash lines in Fig. 4, the emerging end of theblank is bent upwardly to form the elbow. 'Ihe corrugations formed onthe outside of the bend are slightly flattened or drawn out by thebending operation. Y i

The corrugating dies 9 are carried on slidesV 65 (Fig. 2A) which aremovable ony theplate 4 radially of the circular opening 29 therein. Theslides 35 are carried between segmental dovetail guides 55a formed onthe outer side of the plate 4. Reciprocation ofthe slides 65 is electedby an annular rim 66. The ring 66 is rotatably carried by rollerbearings 61 spaced about the plate 4, and is held against movement awayfrom the plate by keepers 58. The keepers are secured'by screws to studs69 mounted o'n the'plate '4. The ring 63 has hardened inserts 15 spacedtherearound for engagement with the' roller bearings 61.

Cam slots 1l are formed at intervals around the ring 66. The outer sidesof these slots are provided with hardened inserts 12. The slides E5 haveroller bearings 13 thereon extending into the slots 1l. By reasonvof theconstruction described, counterclockwise rotation ofthe ring 65 willcauseinward radial movement of the slides 65. Clockwise rotation of thering 66 will cause outward radial movement of the slides. backand forthrotary movement of the ring 65 is provided by a crank arm 14 attachedthereto, an adjustable link 15 and an eccentric 16 on the shaft 23. Y

The oscillation of the ring 66 and the reciprocation of the ratchet bar8 are timed so that the corrugating diesrmove inwardly as .the ratchetbar is retracted, the corrugating dies being withdrawn when the ratchetbar is advanced to feed the Work.Y

Such l Vhub or block 90.

, Bending arms Bearing brackets 11 are carried at the working vend (theleft end, as shown in Fig. 1) of the apparatus, and a shaft 18 isjournaled therein. The ends of the shaft are flattened, as shown inFig. 1. The bending arms |0 are pivoted at 19 on the flattened ends ofthe shaft. The holes in the "arms l0 through which the flattened ends ofthe shaft extend are relieved as at to permit the arms I0 to tilt ontheir pivots 19. Tension springs 8| extend between brackets mounted onthe shaft 18 and.v brackets secured to the lower ends of the arms I0 fornormally holding the arms in `the position illustrated in Fig. 2.

The .arms I0, on oscillation of the shaft 18, are adapted to engage lugs82 formed on the bending ring 6. Such engagement causes the bending ring6 to be deiiected upwardly as successive corrugations are formed in theblank 1, as indicated in dot and dash lines in Fig. 4.

Oscillation of the arms I0 is effected by a downwardly extending link 83keyed tothe shaft 18. A tension spring 84 normally urges a set screw 85at the lower end of the link 33 into engagement with a slide 86 axiallymovable in a guide 81 carried in the bed I. The slide 86 has a roller81a projecting into a slot 88 formed in a barrel cam 89 on the shaft 2|.The oscillation of the arms I0 is thus co-ordinated with thereciprocation of the forming dies 9 and the feed bar 8.

Driving clutch and brake "I9 has a hub provided with driving faces 94adapted to engage the slide 92, as indicated in Fig. 13, wherebyclockwise rotation of the gear I9 drives the hub 90 on engagement of theslide 92 by one of the faces 94. Between the faces 94, the hub isprovided with sloping surfaces 95. Since the slide 92 is normally forcedtoward the gear I9, the latter is normally in driving relation with thehub 90 through which the shaft 22 is driven.

A link 96 pivoted to the bed at 91 is so disposed that its free end maybe moved into the space between the hub of the gear |9 and the The endof the link 96 is rounded as at 98 for cooperation with a similarlyshaped surface 99 on the slide 92. If the link 96 occupies the positionshown in Fig. 3, engagement of the surfaces 98 and 99, as the hub 90rotates clockwise, will cause the slide 92 to be forced back vinto therecess 9 I, thereby freeing the hub from driving relation with the gearI9. Rotation of the latter continues thereafter without effect on thehub 90, until the free end of the link 96 is raised to permit the slide92kto be moved back to the position indicated in Fig. 12. The nextengagement between one of the driving faces 94 of the gear I9 and theslide 92 will cause the hub 90 to move again with the gear I9.

The link 96 is operated from a rock shaft |90 through a linkageincluding links 0| and |62. The link 96 tends to fall by its own weightto the position shown in Fig. 3 in which it causes disengagement of thehub 90 from the gear I9 in the manner already described. It may beraised to permit resumption of the driving relation by tilting the rockshaft |00. The rock shaft |00 is journaled in suitable bearings in theplates 3 and 4, and is provided with a cam block |03. A slide |04 ismounted in bearings |05 on the plates 3 and 4 for longitudinal movement.An operating handle |06 is secured to the slide |94. A cam block |01 isadjustably mounted on the slide |04 for cooperation with the cam block|93. Movement of the slide |04 to the right as viewed in Fig. 1, bycooperation of the cam blocks |93 and |01 causes counterclockwiserotation of the rock shaft |00, as viewed in Fig. 3, to raise the link96. This movement also operates to release the brake 3 to permit freerotation of the hub 99 with the gear I9.

The brake I3 comprises a yoke |98 embracing the hub 90. The yoke ispivoted to the bed at |09 and is split at a diametrically opposite pointto permit contraction thereof for gripping the hub 90 in the manner of afriction brake. The adjacent ends of the yoke, indicated at H0, arenormally urged apart by a spring IiI seated in alined borestherethrough, and backed up by a screw plug II 2. The ends |I0, however,may be caused to approach each other by a camming lever H3. A stud I|4is threaded into the lower end II of the yoke, is freely movable througha hole in the other end I0, and has a pivotal ccnnection l5 with thelower end of the camming lever H3. The lower end of the lever ||3 isbifurcated and extended to provide toes or camming surfaces ||6 engagingthe upper end I I0 of the yoke |98. When the lever ||3 is rotated aboutthe pivot ||5 clockwise, as viewed in Fig. l1, the ends H0 of the yokewill be forced together, and the body of the yoke will be sprungsufficiently to grip the hub 90. Reverse rotation of the lever ||3 willpermit the spring to release the gripping engagement of the yoke |08 onthe hub 90.

The lever IIS is operated simultaneously with the rock shaft |09 fromthe slide |84. A link I I1 is pivotally mounted on a bracket I I8carried on the plate 3, and is pivotally connected to the end of theslide |04 which extends therethrough. The lower end of the link II'I ispivotally connected to the lever 3 by a link ||9. Movement of the slideI |14 to the right, as viewed in Fig. l, thus causes the brake to bereleased and the clutch engaged. Reverse movement of the slide causesdisengagement of the clutch and engagement of the brake. The connectionbetween the link |9 and the lever II 3 is provided by a pin and slot||9a providing a small amount of lost motion. The amount of this lostmotion may be adjusted by a set screw H911 carried on a lug dependingfrom the link H9. By reason of this lost motion, the brake I3 is notapplied until an instant after the clutch has been disengaged, thesequence being, first, the disengagement of the clutch and, after a veryshort interval, the application of the brake to stop the shaft 2|. Theinherent resilience of the yoke |08 causes the brake to be released assoon as the lever |06 has been moved to the right to cause engagement ofthe clutch.

The operation of the device The carriage 3| occupies the positionindicated in dot and dash lines in Fig. 4, at the commencement of anoperating cycle. One end of the tubular blank 1 to be corrugated andbent is rst inserted in the annular' slot in the bending ring 6. Whilethe blank may be formed in any con- Cil venient manner, bending rolls(not shownllmay -well be driven by a shaft |20 which is driven 'by arbelt and pulley drive from the shaft 2|, as shown in Fig. .2. The shaft|20 is journaled in bearings supported on angles |2| extending laterallyfrom the bed The blank is inserted in the ring 6 so that the lap jointis adjacent an index mark |22 on the ring 6 (see Fig. 14). The other endof the blank may then be inserted between the clamping jaws 3l, whichare opened as a result of the engagement of the stud 63 With the slide47. The ring 5 carries a guide tongue |23 adapted to cooperate with aguide plate |24 having a slot |25 therein, one end of the slot beingtapered, as at |26, to guide thev tongue- |23 entering thereinto. Theplate |24 is mounted on top of the bearing bracket 11, as shown in Fig.2. As the blank is pushed back over the mandrel 2, forcing the carriage3| to the right, as viewed in Fig. 4, the tongue |23 is guided into theslot |25` to position the lap joint in the blank accurately on theinside of the bend to be formed therein.

When the carriage 3| is pushed back to the position illustrated in solidlines in Fig. 4, the stud 6| depresses the spring latch-'50 to releasethe pawl 5|. The stud |52 automatically causes the clamping jaws 3l togrip the end of the blank inserted between them and the end of thecarriage 3|. Needless to say, the corrugating dies 9 should be retractedbefore it is attempted to insert the blank into the machine. As` thebending ring 6 approaches the arms |0 during the insertion of the blankinto the machine, the lugs 82 engage divergent wings |27 extendingoutwardly from the arms. Advancement of the ring G causes the arms l toshift outwardly on their pivots 19 to permit the ring to passtherebetween. After the ring has passed t0 arms, the

vspringsl restore them to their normal position in which they cooperatewith the lugs82 to bend the emerging blank.

The machine may be started by pushing the leverl to the right. Thisraises the lever 96 and permits the clutch kl2 to become engaged byadvancement of the block 92? into such position as to be engaged by thedriving surfaces M. 'Ihe brake |23 is simultaneously released as alreadyexplained. Intermittent operation of the -forming dies e, bending armsH3 and ratchet bar 8 proceeds in such co-ordinated fashion assuccessively toV form corrugations, bend the emerging end of the blank,compressing the corrugations on the inside of the bend and flattening orstretching those on the outside, and then notch the blank forward forrepetition of these operations. When the required number of corrugationsand bending impacts have been applied, the carriage 3| Vapp-roaches theplate l andthe detent 55 engages the abutment 59 to place the springlatch 607m the position to engage and hold up the pawl 5|. Engagement ofthe stud 63 by the slide M causes the latter to shift and release theclamping jaws 3l. The clutch may then be disengaged and the brakeengaged by moving the handle |06 to the left, although failure to do sowill not result in any damage, as'the feed means is rendered ineffectiveby the latch G. While op'- eration of the corrugating dies and thebending arms I0 continues until thehandle |06 is shifted, suchoperations will produce no effect in the ab arca-993 sence of aforward'feed'ofthe workpiece. The completed-elbow-may then be 'removedfrom 4the ,carriage-V 3| and, if desired, the flap joint riveted.

The bendingring 6-is removedfrom the blank and the Ymachine is-thenready for a repetition of the operating cycle just described. y Y

It will be apparent from the foregoing description that the invention ischaracterized by nu-V .mechanismforoperating the corrugating dies issimple, sturdy Vand rugged, and therefore not likely to cause diflicultyin operation. The automatic clamping for Aengaging the end of the blankfirstinserted in the machine is highly effectivefto. hold the blankinproper position during the fabricating operationfsince it engages theblank substantiallythroughout the circumference of the latter, andrelease it in ample time for quick removal. The brake operation isautomatically `co-ordinated with the operation of the clutch tostop the.machine instantly when the clutch is disengaged, vpreventing continuedoperation by the momentum' of the rotating parts. Th adjusting meansyincluded in the linkages operating.theratchetbarV and the corrugatingdies permit the several steps of the operation to be timed accurately sothere willbe no interference oroverlapping of operations.

Although I have illustrated and described but one preferred embodimentof the invention, it will be recognized that changes in the constructiondisclosed may be made withoutydeparting from the spirit of theinventionor'the scope of the vappended claims. Y Y

I claim: Y

1.-,Inan elbow forming machine, having a mandrel, :a carriagereciprocablef thereon adapted Vto receive one end of atubular yblank tobe formed into anv elbow, a reciprocable ratchet bar and a pawl on saidcarriage cooperating therewith whereby to advance the carriage stepv bystep; a lever tiltably mounted on said carriage, asecond lever .pivotedthereto, a detent pivoted on the second lever and releasablyV engageablewith the rstVapawl-holding latch on said second lever andfmeans engagedby said detent on movement of the carriage to its extreme forwardposition,.to trip said detent and disengagev the i'lrst` menlcionedlever, -whereby to tilt both said Ylevers and thereby move said latchinto pawl engaging position. 1

2. The-apparatus defined by claiml characterized by means for resettingsaid levers and releasingsaid latch on movement of the carriage to itsextreme rearward position.

3. In anelbow corrugating and .bending machine having feed, Vcorrugatingand bending means, a drivefor said means including a clutch, and abrake; a lever for operatingsaid clutch and alever for operatingV saidAbrake, said levers beingpivoted onv axes at substantially right angles,and common means for actuating said levers comprising .a slide barlinked to one lever, a rock shaft parallel to said bar and having acrank thereon, means connecting the crank to the other lever andcooperating means on the slide bar and rock shaft to cause rotation ofthe latter on reciprocation of the former.

' CHARLES J. HOLUB.

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